Method of making boiler tubing



June ,1925. 1,540,270

G. MAY

METHOD OF MAKING BOILER TUBING Filed Feb. 12 1924 FFE 1 WE, Z,

1N VEZVTUH BE [715' BE AMY Civ Patented June 2, 1925.

; nnzrrsn y g 1,540,270? PaQtT'EINT i I GEORGE MAY, OFSEN FRANCI SUG) CINLIIOENIA AIS IGN'QROF ONE HAEEYTU EMILY SGHMIJJT", OF"'SLAN -FRANCIS'GO, CALIFORNIA; l H

OFI'M'KKINGAiBOIIiERQ TUBING;,

A ppl' lcatiom filed' 'Februaryi 12,1924; Serial 1:1 0; 682,390.

To all whom it may; concern;

Be it known that I, GEORGE Minn, ,acitizen of the United States; residing; at: San Francisco, in the county of San Francisco and "State oftGalifornia, have. invented -v new and 1 useful Improvements in Methods of Making Boiler. 'lnbi-ng, ol which the followingisa specification,

The present invention resideslinthe provisionoti an in iproved=tubing andinethod of making theqsame, which tubing 3 is particularly adaptech for" use iniboilers, stean' generators, Wilt-8'1- hea ters land: the-like, and anall pu'rposcs wh erein tliiids are'heated 111 tubing.

The primary-object of the inventionis to provide a simply constructed alltliCOli-klifiltt- .tively inexpensive tube construction-1 which is ot'"snbstantially; o-vali'orin-in: cross seci nd'provides aigreateriheatingsurface in proportion to" its sectional, area than is provided with: thenusual--round; or! circular t ubing, the 1 method by which the tubing is made licingzmorc sii'i'iple and less expensive to carry-outas compared to methods employed in inakin round tubinm A further ob 'ect of the invention is;; to

provide atubing;construction ott the character: described which mayfb'e quickly and easily *lomedi from elongateth strips of sheet, strap or like metal 'fandwhich, due tothe cross sectional: shape of; the; tubing, will provide for a: quickenheating'ot- Watcror quicker generation of steam,-dependingion theuse of: the tuhing, than is possible with the; ordinaryronnd: on circular tubing; A further object is to provide an improved tubing; construction: and? method of making the: same' which:makes possible the use of a =chQaDe'I-Igradeot'fmetal than: is eniilo-ycd for the usual fb'rm ofrou'n'd "or circular "tubing; without-x sacrificing-- any of the advantages of such round: or; circular tublugs andwith: the added admntages ot cheapness of construction, greater heating area, and quicker heating of the Water.

Vith the above mentioned and other jects in View, the invention consists in the novel construction and combination of parts hereinafter described, illustrated in the accompanying drawings, and set forth in the claims hereto appended, itbeing understood that various changes in the form,

5 proportion, size and minor details of constructionwithin the. scope of; the claims may be resorted to. Withoutv departing; from the spirit or. sacrificingnny of 'tlie advanta ges-of tl ieiinyention. H

Referring, to, the drawing;

Fiv 1 represents a cross sectional View ot'the initial forminto whicl istliestrip' ot metal is bentin the metho'dmof'.forming tlie tubing, the strip. being shown, asibefore" be- 7 ingbent, in dotted lines" V I Fig, 2. represents a, sectional VlQXV of the tubir in"iitsxnexteform.

Fig. 3 represents a: cross oiithe.linishedvtubinga Fig.1; 4 represents a1 perspective View shown-partly in cross section,- .ofthe means employed for bending thezttibing into coils;

Fig. 5' represents a top plan View of, a iinishedcoil ot'rtubingi,consti'uctedl in accordance with the-invention.

In-the 5 present en'ib odiinent of: the intention,-the. tubing is constructed :ti-oi'n an elongated'strip 1i otthin sheet or: strap n ietal, of. any; suitable character, .Whicli'strip is shown-i in; dotted! linesv as before being initially treated in th e carrying out-of my invention; As shown,v in Fig. the first sectional View step in the forming; out the tubing, off niy invention requires i the bending, otffthe strip into channel-or U-fo'mn shownatl-AI- This may be. carried out in any; suitable manner providing for. aquick andjinexpensive- =bending of-;t.he stripv into such-form; rL- er? the strip is bent into channel or U fornn; a length or strip of Wire or otherw substance '2, which illnserveas closure, ,is -mounted inland closes the open side otgth e U shaped tube. Zilhislengthor strip 'of re ort other material is such that it Will fit: snuglyin the strip as shown, said.strip is WeldedQas shown at: 3, in- Fig; 8, to the. sides o'ttlie tubing; preferably being; done/by an. elec tric Welding. By Welding tlie closure-strip' too the open'sid'e ofthetubin After placing V the tubing is made, before the second and third steps are carried out, that is the placing of the closure strip and the welding thereof in place, a bendable metal form re- I taining strip 4 is placedin the U-shaped form of the tubing as shown in Fig. 4, and preferably so that it extends beyond the edges of the open side of the tubing. This strip a is of the proper diameter to maintain the sides of the tubing in parallelism and to maintain the U-shaped form throughout the bending operation. The next step is to place on one side of the tubing a bendable metal spacing strip 5 corresponding in shape and form to the strip 4, and the tubing is then bent in a suitable bending machine, not shown, aroundthe, strip 5 which acts as a spacing member to provide an equal spacing of the coils formed in the bending operation. The strip 5 may be of different thicknesses, as desired, depending on the spacing of the coils desired. Vith the parts assembled as shown in F ig. 4, the assembly is suitably fed into a bending machine which may be operated to form the coil, for example, the coil B, in Fig. 5. After the coil is formed, the second and third operations, in forming the tubing are carried out, the strip or other material 2 being placed in the open side of the coil and then welded as shown in Fig. 8, thus completing the formation of a coil of tubing of the special construction of this invention.

In Fig. 5, there is shown a fiat coil but I do not limit myself to the shape shown as it is obvious that the tubing may be formed into coils of various sizes and shapes. Suitable couplings or joint members, not shown, may be provided for connecting water feed and return pipes, not shown, to the terminalsof the coils, shown in Fig. 5, which coupling members may be welded thereto or 1 otherwise attached as desired, to said terminals.

In carrying out the method and construction of this invention, it is seen that I may use any suitable kind of sheet or strap metal in strips, depending upon the grade or character of the tubing desired, to quickly and easily form the strip into a substantially oval tube, which tube has a greater heating surface in proportion to the cross sectional area or water capacity than is. provided in the ordinary round or cylindrical tubing, with a result that when such tubing'is' used for length of life in boiler and water heater tubing than is possible with the conventional round type of tubing and due to the simplicity of the method followed in making the tubing, a great saving in time and expense in the manufacture of the tubing may be effected. In forming the coils with the use of'the strips at and 5 after'the tubing isbent into'the desired coil form, the strips maybe readily removed by being knocked out with a suitable tool or instrument, not shown, and in some instances, can be lifted out of place.

If desired, the first operation of bending of the strip of metal into U or channel form, may be carried out by making such bend around the strip 4: and the coiling operation may be carried out by then-placing the bendable strip 5 on one side of the U-form and then carrying out the coil forming operation as described. I I 1 I claim: 1

1. The method of constructing tubing in coil form which consists in first bending a stripof metal into channel form, placing a forln retainingbendable strip in the channel of theform, placing a bendable strip on one side of said form then bending the form and strips to form a coil orseries of coils, then removing said bendable strips, then sealing the open side of the channel.

2. The method of constructing tubing in coilform which consists in first bending a strip of metal into channel form, placing a form retaining bendable strip in the channel of the form, placing a bendable strip on one side of said form then bending the form and strips to form acoil or series of coils, then removing said bendable strips, then placing a sealing strip into the open side of said channel, then welding said strip to said .form. V I A coil of substantially flat tubing having a substantially ovicular form in cross section, whichtubing is made up of a sheet of metal bent into channel form and a closing strip welded in the open side of the chan- 

